Anchor rod thread length 1

[cb1331]

Hi everyone. We have run into a problem on a job site. The contractor set the anchor bolts too far into the pier that there is not enough thread on the rod to fully adhere the bolt. I remember seeing a system (I though was Hilti) that can accommodate this site discrepancy.

Any thoughts?

 

[fegenbush]

AISC has a free resource that may be of assistance

https://www.aisc.org/content.aspx?id=2168

If you need to make the threads or length longer, you can use a coupling and another threaded piece to increase the length. You may need to add fabricated spacer plates to allow for the increased diameter due to the coupling.

 

[jayrod12]

Depending on the situation you could weld the nut to the bolt if you are getting partial but not full engagement of the nut.

This is dependent on a few things, shear or tension or both on the bolt, how much partial engagement are you getting, is the anchor bolt of weldable material, to name a few.

 

[bkbstruc]

I recently sat in on an ASCE seminar which showed an example of calculating the pull-out strength of an anchor with a partially threaded nut. Check out "Fastener Design Manual" by Richard T. Barrett if you are able. I can dig up the slides showing the example if you'd like.

 

[Ingenuity]

From AISC's 'Field Fixes' document dated 2006 by Fisher and Kloiber:

 

[Hokie93]

What you need is the Elocone nut by CANAM Steel. This is an elongated nut specially made for this very purpose. They fit anchor rod diameters ranging from 3/4" to 2 1/2". Google "Elocone Nuts".

 

[cb1331]

Thanks everyone - very helpful. And Hokie - that is the nut I was referring to! Thanks for the refresher.